HIV/AIDS Glossary

One of the two types of HIV, the virus that causes AIDS. AIDS is the most advanced stage of HIV. HIV-1 is transmitted through direct contact with HIV-infected body fluids, such as blood, semen, and vaginal fluids, or from a mother who has HIV-1 to her child during pregnancy, delivery, or breastfeeding/chestfeeding (feeding a child one's own milk). HIV-1 is responsible for the majority of HIV cases worldwide. In the United States, unless otherwise noted, the term "HIV" primarily refers to HIV-1.